In income phase, I got a food and a trad chit.So I change them to a worker, and put the worker on another empty building to work(for example make a wood).Finally, I got a worker and a wood in ONE income phase.

No, you cannot use something you gained in the income phase of a turn to get another worker to gain you more income in the same turn. This would be like having one worker and moving it to multiple spots and saying you had a worker there.

On the back of the player screens there is a description of the order of a players turn to help you remember this.